1. Minutiae

2. Origin of Fingerprints
Purpose of friction ridges – to provide a textured surface for gripping and holding on to objects
Friction ridges arise from the dermal papillae layer of the skin.
Ridges start to form at the 8th week of gestation and are done by the 17th week of gestation
From that point on, fingerprints never change; they only grow larger as the body grows

3. Origin of Fingerprints

4. The Origins of Fingerprints
Sweat glands form in the dermis and terminate as sweat pores on the ridges
Perspiration is discharged from the sweat glands and exits through the pores onto the surface of the ridges
Perspiration along with sweat, skin cells, proteins, fats, and other materials are deposited when a finger touches a surface.
These invisible fingerprints are called latent prints.

5. Three types of Fingerprints
Latent prints – a fingerprint that is not visible to the unaided eye
Patent prints – a visible fingerprint deposited via a substrate such as blood, grease, or paint
Plastic prints – a visible fingerprint impression deposited by contact with a soft material such as putty

6. Patent and Plastic Prints

7. Origin of Sweat Glands

8. The Anatomy of Fingerprints
A fingerprint consists of the friction ridge skin of the last joint on each finger taken from cuticle to cuticle
Major ridge shapes:
Ending Ridges
Bifurcations (also known as a fork)
Trifurcations
Dots (also known as a very short ridge)
Island ridges (also known as a short ridge)
Enclosures (also known as an eye or island)
Bridge (also known as a crossover)
Spur (also known as a hook)
Double bifurcation

9. Ending Ridge
A simple straight ridge that ends

10. Bifurcations and Trifurcations
A ridge that splits into two ridges at the end
Trifurcations:
Just like bifurcations but split into three ridges at the end

11. Dots and Short Ridges Dots – tiny round ridges
Short ridge – a small, isolated segment of ridge

12. Enclosure
A ridge that forks and forms a complete circle and then becomes a single ridge again

13. Taken together, the ridge characteristics of a fingerprint
Taken together, the ridge characteristics of a fingerprint. The types and locations of specific minutiae impart the uniqueness that is the basis for comparison of fingerprints.
Minutiae